Mountain Gorillas

After chimpanzees, mountain gorillas, the largest of all the great apes, are the most closely related primates to human beings. Inhabiting the dense forests of tropical Africa, mountain gorillas were encountered relatively recently for the first time by a non-African in 1902. Since then, they have become an iconic symbol of the African wilderness.

Distribution

It is believed that approximately only 720 mountain gorillas survive today in the dense forests of the border between the Democratic Republic of the Congo (DRC), Rwanda and Uganda. Within these countries, there are two distinct populations, confined to four national parks. These populations are separated by two forest blocks less than 45 kilometres apart. One population numbering approximately 340 individuals is found in the Bwindi Impenetrable National Park in Uganda, while the other, thought to consist of around 380 gorillas, is found in the habitat shared by Mgahinga Gorilla National Park in Uganda, Volcano National Park in Rwanda, and Virunga National Park in the DRC.

Endangered Status

Declining populations of mountain gorillas has led to their listing as ' ˜Endangered' on the World Conservation Union (IUCN) Red List of Threatened Species. This list is designed to determine the relative risk of extinction, and the endangered classification emphasises the vulnerable future of these majestic animals in the face of increasing pressures.

Social Structure

Despite their large size and powerful demeanour, mountain gorillas are generally shy and gentle. They live in stable and cohesive family groups that are led by a dominant silverback male, named for the silver hairs that grow on the back of mature males at the age of between 12 and 15 years. While family groups with more than one adult male do occur, most groups consist of one silverback and many females. The number of gorillas in these family units averages around 11 but can consist of as many as 40 individuals. The remaining males in gorilla populations are either lone males or form exclusively male groups. Silverback males are critically important to the family group dynamics, directing their movements by deciding where to forage and sleep, and protecting the group from rival silverbacks and human threats.

Female gorillas are able to give birth for the first time when they reach 10 years of age, and then only at least every 4 years. Over her whole lifetime, a female mountain gorilla may only have 2 to 6 offspring. This slow reproductive rate makes this species even more vulnerable to escalating threats.
Threats

Mountain gorillas are becoming increasingly threatened by climate change, habitat loss, poaching, human disease, and civil conflict. Their restricted distribution in small areas of dense forest, between altitudes of 2,500 and 4,000 m, and surrounded by a high human population density, restricts the ability of these animals to physically avoid encroaching threats. This makes them particularly susceptible to increasing temperatures resulting from climate change. It is thought that an increase in ambient temperature of even 1ÂºC could change their habitat so that it is no longer suitable for them to feed and survive in.

This problem is exacerbated by the habitat destruction that is occurring all around them. The growth of nearby human settlements is increasing the demand for land, food and timber, leading to escalating logging practices. Not only does this further restrict their available habitat, but land clearing in Central Africa also contributes more greenhouse gases to the atmosphere than any other land-use practice on the continent. As well as contributing to global climate change, this habitat loss has a direct effect on the local climate by reducing the amount of precipitation in the rainforests, which has been shown to correlate to a decreased richness of plant species, the major food of mountain gorillas.

Already in a vulnerable position, mountain gorillas are facing even more direct threats at the hands of humans. Poaching has been a significant threat to their survival since they were first discovered by non-Africans in the early 1900s. In the first two decades, over 50 mountain gorillas had been killed by scientists and trophy hunters, and the effects of poaching are still seen to this day. Infants are poached to be sold as pets or to zoos, adults die defending their family group or for the sale of their heads, hands and feet, and they are sometimes an unfortunate victim of unselective hunting with snares intended to catch other wildlife. Poaching is known to occur in all three countries where mountain gorillas are found.

A further threat is from the burgeoning tourism industry, which has increased the contact between mountain gorillas and people. Owing to our genetic similarity, mountain gorillas are vulnerable to many of the same diseases as humans, however they have not yet developed the necessary immunities. This increased risk of infection means that the first exposure to an illness or virus that is relatively harmless to humans has the potential to devastate an entire population.

To read about HSI's campaign to stop the slaughter of the Mountain Gorillas click here